Why sakoku?

Despite one incredibly waffly professor, I learnt quite a lot from this BBC radio programme on the policy of closing Japan to (most) foreign contacts in the Edo period. One thing that it wasn’t such an unusual policy because the Chinese had attempted to do the same more than once before. They also mentioned that because Japan was self-sufficient most imports were fripperies, something frowned on in zen-inspired samurai bushido culture. The main reason, however, seems to be that unrestricted trade would have enriched the rather independent-minded Kyushu daimyo lords.